1. Field of the Invention
This invention concerns the structure of a chamber that is for use in making gamma ray emission measurements of a fluid that is subjected to bombardment from a neutron source.
2. Description of the Prior Art
A recent patent, U.S. Pat. No. 4,190,768, issued Feb. 26, 1980, deals with a system for determining the water cut and water salinity in an oil-water flow stream by measuring the chlorine and the sulfur content of the produced oil. Such system includes a chamber through which the fluid stream flows. The chamber is the location for instrumentation that makes the desired determination by bombarding the fluid with neutrons, and high energy gamma rays resulting from capture of thermal neutrons are detected. Then, the spectra of the detected gamma rays are analyzed to determine the relative presence of the elements, sulfur, hydrogen and chlorine. In that system the chamber employed for mounting the instrumentation is preferably manufactured of some material which contains no elements producing appreciable capture gamma radiation above 5.0 Me V. However, as indicated if the material used is iron, it would be desirable to coat the internal surfaces of the chamber with a material of high thermal neutron cross capture cross section, e.g. by painting on a boron carbide, epoxy mixture. But, while that technique reduced the background noise there were difficulties which involved such problems as the surface of the coated area not being smooth so that the erosion of material was high. Also, the coating technique was time consuming and costly, plus the fact that problems were encountered in curing the mixture. In addition, the coating did not turn out to be uniform in thickness and so tended to result in increased background noise.
Consequently, it is an object of this invention to provide an improved chamber structure that makes a highly satisfactory protective layer of boron carbide readily applicable to the desired surfaces of a chamber to be used for the indicated gamma ray emission meaurement.